Quick answer
Polybutylene is a gray, sometimes blue or black, flexible plastic water pipe installed in millions of US homes from about 1978 to 1995. It can become brittle and crack from the inside, so it often fails without warning, and many insurers and buyers ask about it. Look where pipes enter the water heater and at the main shutoff for gray pipe stamped PB2110. Replacement means repiping with PEX or copper; HomeAdvisor puts a whole-house repipe at about $4.50 per square foot of house. Call (888) 217-6781 to reach a plumbing company taking calls in your ZIP.
Follow the short menu, then your 5-digit ZIP. The line goes quiet for a few seconds while it connects; stay on. If it does not connect, call once more: companies taking calls change minute to minute.
Written & reviewed by Marcus ReedIICRC WRT
Reviewed November 4, 2026· Next review May 2027
Polybutylene was a low-cost plastic water supply pipe used widely in US homes from about 1978 to 1995. It was later found to become brittle and crack, especially where chlorine in the water attacks it from the inside, so it tends to fail without warning rather than slowly. Production stopped in the mid-1990s after large class-action litigation, but many homes still have it. To see which states built the most homes in those years, see home plumbing age by state.
How to Identify It
| Where to look | What polybutylene looks like |
|---|---|
| Pipes into the top of the water heater | Gray, flexible plastic, sometimes with a short metal or flex connector |
| The main shutoff where water enters | Gray or blue plastic; blue or black outside |
| Under sinks and behind toilets | Gray pipe coming out of the wall to the shutoff valve |
| The pipe itself | Often stamped PB2110 |
| The fittings | Gray plastic fittings, or copper or aluminum crimp rings |
Do not confuse it with PEX, the modern plastic pipe, which is usually red, blue or white and stamped PEX. Gray CPVC is rigid, not flexible.
Signs It Is Failing
- Small leaks at fittings, or pinhole leaks in the pipe.
- A water bill rising for no reason; see high water bill: how to find a leak.
- A previous repair where one section has already been replaced.
- Flaking or brittle pipe where it is visible.
Talk to a plumber about this
One call reaches a plumbing company taking calls in your ZIP.
Should You Replace It?
There is no requirement to replace it, but the risk is the failure mode: a pipe that splits inside a wall or ceiling can flood a room before anyone notices. See pipe burst in wall. Some insurers ask about it, and buyers' inspectors flag it. Most owners who keep it at least install a leak detector and know where the main shutoff is.
What Replacement Costs
Replacing polybutylene means repiping the supply lines with PEX or copper. HomeAdvisor puts a whole-house repipe at about $4.50 per square foot of house, with labor about 70% of the total. Angi puts pipe material at $0.40–$2 per foot for PEX and $2–$8 per foot for copper. See repipe house cost and repiping.
The Call
Call to have a plumber confirm what pipe you have and quote a repipe, or right away if a polybutylene fitting or pipe is leaking. (888) 217-6781 connects you to a plumbing company taking calls in your ZIP. Follow the short menu, enter your 5-digit ZIP and stay on while it connects; if it does not connect, call once more, because the companies taking calls change minute to minute.
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Frequently Asked Questions
What years was polybutylene pipe used?
Roughly 1978 to 1995 in the United States. Homes built or replumbed in that window are the ones to check.
How do I know if I have polybutylene pipes?
Look for flexible gray, blue or black plastic supply pipe, often stamped PB2110, at the water heater, the main shutoff and under sinks. Fittings may be gray plastic or have copper or aluminum crimp rings.
Do I have to replace polybutylene pipes?
There is no law requiring it, but the pipe can fail without warning, and some insurers and buyers treat it as a reason to decline or ask for a credit. Many owners replace it before it leaks.
How much does it cost to replace polybutylene pipes?
HomeAdvisor puts a whole-house repipe at about $4.50 per square foot of house, with labor about 70% of the total.
Sources
Methodology: How we source and verify data · Report an error
Disclaimer: HearthDry is an independent educational resource. This article is for informational purposes only and does not constitute professional, legal, or insurance advice. Consult licensed professionals before making decisions about your property or insurance claims.
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